Option to consolidate the Menu Button and Address "Bars" in windowed mode

Out of all the relevant browsers in W10 (Chrome, Firefox, Opera, Vivaldi), while in windowed mode and with the bookmarks bar open, Opera is the one that takes the most vertical space of them all.

This is directly related to the whitespace generated by the Menu/Opera button sitting alone at the top sharing a "bar" with the minimize/maximize/close buttons.

Therefore I would love the option to be able to emulate the behavior of the maximized window (in which both the menu/min/max/close buttons and the Tabs share the same vertical space or "bar") while in windowed mode, in order to show the most amount of web content possible.